Automatic firearm



J. DOBREMYSL Jn. is, 1945.

AUTOMATIC FIREARM Filed Nov. 5, 1940 4 Sheets-Sheet 1 frz van for.'

JOSEF .003@ fwn/.s1

Jann E6, 1 DOBREMYSL 2,367,488

AUTOMATIC FIREARM Filed Nov. 5, 1940 4 Sheets-Sheet 2 In ve niorJUSEFOB/EE/VYSL @gg-fg Jan. 16, 1945. J DOBREMYSL 2,367,488

AUTOMATIC FIREARM Filed Nov. 5, 1940 4 sheets-sheet 3 Y -FIG.4.

Inveniar" Jan. 16, 1945.

J. DoBREMYsL. 2,367,488

AUTOMATIC FIREARM Filed Nov. 5, 1940 4 sheets-sheet 4 F IG.7.

@Ei i X wx i Y 54 5S se so 57 fn ven for l .70.55F llos/'MM L PatentedJan. 16, 19.45

Urrea sTA'rlazsA PATENT oFFIcE Application November 5, 1940, Serial No.364,351

in Great Britain November 8, 1939 2 claims. l (o1. ssa- 33) .The objectof the invention is to provide a feed operating mechanism for guns ofthe types referred to which shall be reliable in operation,

of a simple and. robustl construction and of a comparatively light.weight which does not appreciably increase with the calibre of theWeapon.

The present invention relates to guns of the type in which the movementof the feed mechanism is derived from the kinetic energy of therecoiling breech mechanism and the main feature of the present inventioncomprises an arrangement according to which the kinetic energy of thebreech mechanism is transmitted to the feeding mechanism -by means of amember capable of a rocking motion.

In a preferred embodiment ofthe invention the kinetic energy of thebreech mechanism during the later stage of its recoil movement istransmitted to the'feed mechanism by means of a rocking lever.

The rocking movement of the lever is transmitted to the carriage of thefeed mechanism by means of a crank arm and link.

According to a further feature of the invention the active part of thebreech mechanism is shaped so thatyvhen the rear end thereof engages therear arm of the rocking lever the fore arm of the lever simultaneouslyengages the shaped edge or surface of the breech mechanism. y

The arrangement is such that the lever is` positively guided on thebreech mechanism at two points on either side'of its pivot so that anysudden'impact movement is avoided.

The upperV side of the fore arm of the lever may co-operate withthecover or with any other part of the lire arm,to limit the rockingmovement of the lever. A spring may be arranged to return the lever intoits initial position.

It is an important advantage of the invention, that it allows thefeeding of the cartridge belt from either sideY of the iire arm.` Forthis purpose guiding means for the transmitting rod are arranged at eachside of the arm, so that by inserting the rod into the'respective guidethe device may be used for feeding the cartridge belt .from eitherside'of the arm.

Two embodiments of the invention are shown by way of example in theaccompanying drawings.

Fig. l is a vlongitudinal section through the central part of the gun. Y

Fig. 3 is a plan View of the central part of the gun as illustrated inFig. 1 with the'cover of the feed box removed and with retractedtransmitting link of the gun.

Fig. 4 is a sectional View along the line IV--IV of Fig. l.

Fig. 5 is a longitudinal section through the central part of the gun inthe position the gun parts occupy during the recoil movement.

Fig. 6 is a longitudinal section through the central part of the gun inthe position the gun parts occupy during the return movement.

Fig. '7 is a longitudinalsection through the central part of anothertype of the gun as illustrated in the Figs. 1-6.

Fig. 8 is a longitudin-al section throughthe central part of the guntype illustrated in Fig. 7 but in another position of the relevant gunparts.

In the embodiment of theA invention, shown in Figs. 1-6, the gun is ofthegas operated type. The lbarrel I is provided at a suitable point onits length with a channel (not shown) through which gases from thebarrel may enter a gas cylinder and operate a piston, mounted therein-for to and fro movement. Such an arrangement is Well known and need notbe described in detail.

A piston rod 2 is connected or made integral 'at one end with thepiston, the other end being connected or made integral with a breechblock carrier 3. A recoil spring 4, housed in the lbutt 5 acts upon thecarrier 3 by the intermediary of a rod 6, urging the carrier 3 and theparts connected therewith in forward direction. A breech block 'l of thetilting type is arranged for co-operation With the carrier 3. In theposition shown in Fig. 1 the breech block 1, having the cartridge 8 intothe barrel chamber, has been raised by the carrier 3 into a positionwherein the rear surface 'la of the breech block 1 is locked against alocking shoulder 9.

A firing pin lll is housed in the breech block; the firing pin isadapted to be struck by the carrier 3 in the last part of its forwardmovement to re the cartridge.

The breech block comprises further an ex-v tractor II held in properposition by a spring loaded plunger I2.

An .ejector i3 is mounted in the casing of the gun and is adapted forengagement with empty cartridge cases, drawn back by the extractor, toeject the spent cartridge cases out of the gun.

The trigger mechanism of the gun consists of a scar I4 capable ofengaging a corresponding notch I in the carrier 3 and retaining thelatter in retracted position. The sear may be actuated by 4a, link i6operated by a trigger lever` I1, which is mounted rotatably on a pivotI8. If the trigger lever i1 is pulled, the link I6 engages the lower armof the sear and swings its upper arm out of engagement with the carrier3, freeing it for movement under the influence of the recoil spring 4.

In the rear part of the casing I3 of the gun a lever 2i) is rigidlysecured between its ends on a shaft 2| (see Fig. 4). In normal positionthe rear arm 23a of the lever 2U, lies in path of the rear surface 1a.of the breech block 1 as' shown in Fig. l. A spring 22 may be used toensure that the lever 20 is kept in this position or returned to itafter being rocked out, as will be described hereinafter. This spring,however, is not essential. The fore arm 2Gb of the lever 28 is adaptedto yco-operate with a. rib or shaped surface 23, Fig. 6 on the breechblock 1, as will be more fully explained with reference to Figs. 5 and6.

The shaft 2l is connected or made integral with a crank arm 24, thelatter being provided with a slot 25 for co-operation with a projection25 on a transmitting link 21. The link 21 is mounted for longitudinalmovement in suitable guides on the casing of the gun (see Fig. e). Theguides are preferably arranged on both sides of the gun to make possiblethe use of right or left hand feed of cartridges.

The link 21 is provided at its fore end with a stone 28 (see Figs. 2 and3).

A feed box is mounted on the central part of the gun, said feed boxcomprising a casing 2S with suitable guiding means for the cartridgebelt 30, i. e. enlarged mouth 3| for receiving the full cartridge beltand a guide 32 for guiding the empty cartridge belt out of the gun. Afeed carriage 33 (Fig. 2) is mounted for to and fro movement intransverse direction in the casing 29 of the feed box. A feeding pawl 34is carried by the carriage 33, said pawl serving to push the cartridgebelt through one feeding step upon feeding movement of the feedcarriage. The feed box is closed by a cover 35 carrying the retainingpawl 36 which retains the cartridge belt in position.

The feed carriage 33 is provided on its lower surface with a cam groove31 (see Fig. 3), adapted to co-operate with the stone 28, of the link21, in such a way, that if the stone moves rearwardly, in the directionof the arrow A the carriage 33 moves in the direction of the arrow B,Fig. 3.

The device operates as follows:

After the shot has been fired the carrier 3 moves backwards under theinfluence of the gas pressure acting on the piston. During this movementthe rear part 38 of the carrier releases the rear transverse 39 on thebreech block for downward movement and during further backward movementof the carrier 3 its inclined face 68 engages the transverse 39 andtilts the breech block out of engagement with the locking shoulder 9.The breech block gets embedded into the inner space of the carrier (seeFigs. 5 and 6) and moves back with the carrier 3 as one unit. Duringthis further movement the rear upper surface 1a of the breech blockabuts the curved rear part of the lever 20 which is thus rocked in thedirection of the arrow C in Fig. 5. This movement is transmitted by theintermediary of the shaft 2| and crank arm 24 to the link 21 which isthereby moved in rearward direction (direction of arrow D in Fig. 5).The stone 28 (Fig. 3) being integral with the link 21 takes part in thismovement and by the intermediary of the inclined or cam groove 31imparts to the feeding carriage a transverse movement in the directionof the arrow B in Fig. 3. The feeding pawl 34, which at the beginning ofthis movement has been in engagement with that cartridge in the beltwhich had to the brought next into feeding position, has during thismovement shifted this cartridge into register with the breech block 1,as shown in Fig. 3. The belt is Yretained in this position by the re'-taining pawl 36.

During a part of the recoil movement of theV breech block when the reararm 20a of the lever 20 is in engagement with the rear surface 1a of thebreech block, the fore arm 2Gb of the lever 20 engages simultaneouslythe surface or rib 23 on the breech block, as is shown in Fig. 5. Inthis manner a controlled guiding of the lever 2li at two :pointson'either side of the axis of rotation of the lever 2U is obtained, sothat the lever 20 is positively guided and a uniform movement ensured.

Upon the return movement of the carrierbreech block unit the rear upperpart 1b of the breech block engages the forearm 20h of the lever 20 andswings the latter back into its original position (arrow E in Fig. 6).This movement is transmitted by the shaft 2l, crank 24 to the link 21and stone 28, which move in the direction of arrow F in Fig. 6. Thestone 28 moving in the cam groove 31 imparts to the feed carriage amovement in the direction from left to right in Figs. 2 and 3. Thefeeding pawl, moving together with the carriage 33 slides under the nextcartridge to the right and springs behind this cartridge, prepared for anew feeding step.

The upper part of the fore arm 20h of the lever 20 is preferably made asan abutment cooperating with the upper surface of the casing I9 (seeFig. l) to limit the movement of the lever 20.

Figs. '1 and 8 show the invention as used in connection with anothertype of gun of the tilting breech block class. In this gun the movementof the breech mechanism is derived from the recoil of the gun instead ofthe gas pressure.

The breech mechanism itself and the whole feed mechanism are similar tothose of the previous example so that no detail reference need be madeto these parts.

The gun mechanism asl a whole is mounted for a short recoil movement ina guide arranged on the mounting 50 of the gun. The barrel 5l isconnected with a sleeve 52 carrying a pivot 53 on which an acceleratinglever 54 is mounted for rocking movement. The mounting 50 of the gun isprovided with a projection 55 extending into the xpath of the lower armof the lever 54. The upper arm of the lever 54 is adapted to engage thefore end of the ca'rrier 56.` The latter is biased by a recoil spring 51and adapted to co-operate with a breech block 58 in the same manner ashas been described in connection with the first example.

Fig. 7 shows the mechanism of the gun in a position in the moment offiring the cartridge 59. In this position the lever 54 is clear of theproection 55. The breech block is in locked posiion.,

Fig. 8 shows the'parts of the gun in a position shortly after the recoilmovement of the mechanism has started.

The barrel 50 together with the accelerating lever 59 and othermechanisms move back under the inuence of recoil forces. After a shortrearward movement the lower arm of the accelerating lever 59 strikesagainst the projection 55 and is rocked by the latter in clockwisedirection (see Fig. 8). The upper arm of the lever 54 engages with thefront face of the carrier 56 and imparts to the latter an impulse inrearward direction so that from this moment the carrier begins to movefaster than the barrel. The latter returns then to its fore position andthe carrier continues its rearward movement during which it unlocks thebreech block, as has been previously described, and moves back togetherwith the latter. During this movement the upper surface of the breechblock 58 comes into engagement with the lever 59 which is similar to thelever 2D of the first example, and actuates the lever 59 in the samemanner as has already been described.

It is a particular advantage of the invention that the device may beeasily arranged for feeding from either side. For this. purpose a guide60 is arranged also on the right hand side of the gun, see Fig. 4, andto change from one side to the other it is only necessary to insert atransmitting link, which is symmetrical to the link 21,

into the guide 60 and to set the crank arm 2|-24 30 accordingly, asshown in dotted lines in Fig. 4. The guides may be arranged eitheroutside or inside the body of the gun.

I claim:

1. A device for operating the cartridge belt feed mechanism of machineguns comprising a casing, a belt feed carriage, a breech block having asteering portion on its surface, a rocking member with a shaft having apart engaged for sliding engagement with said steering portion of thebreech block, a crank on the shaftv of the rocking member, a linkconnected with said crank by connecting members capable of transformingthe swinging movement of the rocking member into a rectilinear movementof said link, a guide on oneside of said casing in which said link ismounted for longitudinal movement and a second guide on the other sideof said casing, in which the said link may be mounted to slide also 'inlongitudinal directions, and means on said link for operating thecartridge belt feed mechanism.

2. A device for operating the cartridge belt feed mechanism of machineguns comprising a casing, a belt feed carriage, a breech block, havingsteering ribs on its surface, a rocking lever with a shaft and two armseach having a part adapted to slidably engage one of said steering ribsof said breech block, a crank on the shaft of the rocking lever providedwith a slot, a link having a bolt fitting in said slot of the rockinglever in such a manner that the swinging movement of the rocking leveris transformed in a 'rectilinear movement of said link, a guide for saidlink on said casing in which said link is capable of sliding inlongitudinal direction, and means on said link for operating thecartridge belt feed mechanism.

JosEF DoBREMYsL.

